RESUMEN
ABSTRACT: Suhara, H, Nariai, M, Takagi, T, Akiyama, K, Nagashima, J, and Shiraki, H. Relationship of clubhead speed with explosive power and muscle strength of the hip and trunk joints of elite golfers. J Strength Cond Res 37(4): 859-865, 2023-In golf, the driving distance of the ball is affected by the clubhead speed (CHS) on impact. We aimed to clarify the relationship between CHS and explosive power and muscle strength of the hip and trunk muscles in elite golfers (male age: 19.6 ± 1.9 years, male handicap: 4.4 ± 0.9, female age: 17.7 ± 1.4 years, and female handicap: 6.2 ± 0.7). A correlational design was used to assess the relationships between CHS and strength (hip extension-flexion and trunk rotation of peak torque at an isokinetic 60 and 180°·s -1 angular velocity) and CHS and power (countermovement jump [CMJ]; peak power and jump height; backward overhead medicine ball [BOMB] throw). Fourteen each of male and female elite golfers were included. The CHS during the golf swing was measured using a Doppler radar measurement device (Trackman). A correlation analysis between each measurement and CHS ( p ≤ 0.05) was conducted. We found that the peak torque of right hip extension at an angular velocity of 180°/s (male, r = 0.67; female, r = 0.61), peak CMJ power (male: r = 0.63, female: r = 0.75), and BOMB throw distance (male, r = 0.6; female, 0.6) were positively correlated with CHS in both male and female golfers. These results suggest that the extensor strength of the lower extremities and trunk, centered on the hip joint in the sagittal plane, is important for physical fitness and muscle strength measurement related to CHS. Conversely, concentric trunk rotator strength and CHS were not correlated, suggesting that concentric trunk rotator strength may not be actively involved in CHS.
Asunto(s)
Rendimiento Atlético , Golf , Humanos , Masculino , Femenino , Adolescente , Adulto Joven , Adulto , Rendimiento Atlético/fisiología , Torso , Cadera , Articulación de la Cadera , Fuerza Muscular/fisiología , Golf/fisiología , Fenómenos BiomecánicosRESUMEN
The antitumor drug paclitaxel has low water solubility, and its bioavailability is limited by the dissolution rate. To overcome this low water solubility, the currently marketed drug, Taxol, is formulated in a vehicle including Cremophor EL and ethanol mixture (1/1, v/v). However, Cremophor EL has been shown to have serious adverse side effects, such as hypersensitivity reactions and neurotoxicity. Improving the solubility of paclitaxel makes it possible to reduce side effects and enhance drug efficacy during antitumor therapy. One way to improve the solubility of poorly soluble drugs is to decrease their particle size to the nano-range to increase the surface area and dissolution rate. In the present study, we aimed to develop a new method for paclitaxel nanoparticle production. Polymeric nanoparticles of paclitaxel were prepared by laser irradiation at 1064 nm, which is the wavelength in the near-IR region. The prepared nanoparticles had a mean size of 57.9 nm and were spherical in shape. X-ray powder diffraction analysis showed that paclitaxel in the nanoparticles was in an amorphous state. These results demonstrate that the preparation of nanoparticles by laser irradiation is effective in improving the solubility of paclitaxel. Furthermore, the nanoparticles had an equivalent efficacy to Taxol in cell growth inhibition against breast cancer MCF-7 cells and drug efficacy in MCF-7 tumor-bearing mice as determined using positron emission tomography. Our method for preparing paclitaxel nanoparticles may be more effective in treating tumors with fewer adverse side effects than conventional Taxol.
Asunto(s)
Antineoplásicos Fitogénicos , Nanopartículas , Animales , Antineoplásicos Fitogénicos/farmacología , Rayos Láser , Ratones , Paclitaxel/farmacología , Tamaño de la PartículaRESUMEN
The purpose of this study was to identify the dynamic factors contributing to pelvis angular velocity about its longitudinal axis (pelvis axial angular velocity) during the golf swing. Thirty-one right-handed skilled golfers (handicap, 3.5 ± 1.8) performed swings with a driver. The kinematic and kinetic data were collected using an optical motion analysis system and two force platforms. The dynamic factors (i.e., joint torque, gravitational force, motion-dependent forces and inertia forces) contributing to pelvis axial angular acceleration were calculated. The present study revealed that the left (lead) hip flexor and adductor torques as well as the right (trail) hip extensor and abductor torques were identified as the main contributors to pelvis axial angular velocity. These hip joint torques contributed not synchronously but sequentially to the pelvis. Although the knee joint torques contributed little to pelvis axial angular velocity directly, the knee joint torques might support the generation of large hip joint torques by regulating joint postures. These findings indicate that the functional coordination of the lower limb segments as well as the magnitude of the joint torques play an important role in rotating the pelvis.
Asunto(s)
Golf/fisiología , Extremidad Inferior/fisiología , Movimiento/fisiología , Músculo Esquelético/fisiología , Pelvis/fisiología , Adolescente , Adulto , Fenómenos Biomecánicos , Femenino , Humanos , Cinética , Masculino , Rotación , Torque , Soporte de Peso/fisiología , Adulto JovenRESUMEN
The purpose of this study was to identify the detailed mechanism how the maximum throwing arm endpoint velocity is determined by the muscular torques and non-muscular interactive torques from the perspective of the dynamic coupling among the trunk, thorax and throwing and non-throwing arm segments. The pitching movements of ten male collegiate baseball pitchers were measured by a three-dimensional motion capture system. Using the induced-segmental velocity analysis (IVA) developed in this study, the maximum fingertip velocity of the throwing arm (MFV) was decomposed into each contribution of the muscular torques, passive motion-dependent torques due to gyroscopic moment, Coriolis force and centrifugal force, and other interactive torque components. The results showed that MFV (31.6±1.7m/s) was mainly attributed to two different mechanisms. The first is the passive motion-dependent effect on increasing the angular velocities of three joints (thorax rotation, elbow extension and wrist flexion). The second is the muscular torque effect of the shoulder internal rotation (IR) torque on generating IR angular velocity. In particular, the centrifugal force-induced elbow extension motion, which was the greatest contributor among individual joint contributions, was caused primarily by the angular velocity-dependent forces associated with the humerus, thorax, and trunk rotations. Our study also found that a compensatory mechanism was achieved by the negative and positive contributions of the muscular torque components. The current IVA is helpful to understand how the rapid throwing arm movement is determined by the dynamic coupling mechanism.
Asunto(s)
Brazo/fisiología , Béisbol/fisiología , Aceleración , Fenómenos Biomecánicos , Codo/fisiología , Articulación del Codo/fisiología , Humanos , Masculino , Movimiento/fisiología , Rango del Movimiento Articular/fisiología , Rotación , Hombro/fisiología , Torque , Torso/fisiología , Articulación de la Muñeca/fisiología , Adulto JovenRESUMEN
Since clubface orientation at impact affects ball direction and ball spin, the ability to control clubface orientation is one of the most important skills for golfers. This study presents a new method to describe clubface orientation as a function of the clubshaft motions (i.e., swing plane orientation, clubshaft angle in the swing plane, and clubshaft rolling angle) during a golf swing and investigates the relationships between the clubshaft motions and clubface orientation at impact. The club motion data of driver shots were collected from eight skilled golfers using a three-dimensional motion capture system. The degrees of influence of the clubshaft motions on the clubface orientation were investigated using sensitivity analysis. The sensitivity analysis revealed that the swing plane horizontal angle affected the clubface horizontal angle to an extent of 100%, that the clubshaft angle in the swing plane affected both the clubface vertical and horizontal angles to extents of 74 and 68%, respectively, and that the clubshaft rolling angle affected both the clubface vertical and horizontal angles to extents of -67 and 75%, respectively. Since the method presented here relates clubface orientation to clubshaft motions, it is useful for understanding the clubface control of a golfer.
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Golf/fisiología , Destreza Motora/fisiología , Equipo Deportivo , Adolescente , Fenómenos Biomecánicos , Femenino , Humanos , Masculino , Movimiento (Física) , Estudios de Tiempo y MovimientoRESUMEN
Nanoparticle formation of poorly water-soluble drugs is a means of providing much benefit for improving solubility and bioavailability. We showed that laser irradiation of drugs can be a novel tool for dispersing drug nanoparticles in water. Using our method, we were able to produce nanoparticles containing immunosuppressant drug, cyclosporin A, which shows poor solubility toward water, with high levels of the drug using polyvinyl pyrrolidone and sodium dodecyl sulfate as stabilizing agents. The absence of degradation products was confirmed and the loss of pharmaceutical activity with an inhibitory effect on the interleukin-2 production of Jurkat T cells did not occur. Cyclosporin A nanoparticles showed a spherical shape and their particle size was distributed uniformly around 200 nm. Powder X-ray diffraction analysis suggested that cyclosporin A in the nanoparticles was in an amorphous state. In the measurement of solubility rate, the nanoparticle formulation showed a higher rate than that which had not been processed. At present, although this laser irradiation technology has low productivity, it is expected as a new technology for drug nanoparticle manufacturing together with the development of a new laser device.
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Ciclosporina/química , Sistemas de Liberación de Medicamentos , Inmunosupresores/química , Terapia por Luz de Baja Intensidad/métodos , Nanopartículas/química , Ciclosporina/análisis , Citocinas/análisis , Portadores de Fármacos , Composición de Medicamentos/métodos , Humanos , Inmunosupresores/análisis , Interleucina-2/análisis , Células Jurkat , Tamaño de la Partícula , Polímeros/química , SolubilidadRESUMEN
Phosphatidylinositol-3,4,5-trisphosphate (PtdInsP(3)) regulates diverse cellular functions, including cell proliferation and apoptosis, and has roles in the progression of diabetes and cancer. However, little is known about its production. Here, we describe fluorescent indicators for PtdInsP(3) that allow a spatio-temporal examination of PtdInsP(3) production in single living cells. After ligand stimulation, PtdInsP(3) levels increased to a larger extent at the endomembranes (that is, the endoplasmic reticulum and the Golgi) than at the plasma membrane. This increase was found to originate from in situ production at the endomembranes, a process stimulated directly by receptor tyrosine kinases endocytosed from the plasma membrane to the endomembranes. The demonstration of PtdInsP(3) production through receptor endocytosis addresses a long-standing question about how signalling pathways downstream of PtdInsP(3) are activated at intracellular compartments remote from the plasma membrane.